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A Scintillator-PMT combo is used to measure the energy spectrum from a Na-22 source. Calculate the energy of the Compton edge highlighted in the spectrum. Calculate the pulse amplitude associated with the above Compton edge, given: . Scintillation efficiency = 12% . Wavelength of scintillation photon = 410 nm . Light collection efficiency = 60% . Photocathode quantum efficiency = 30% . PMT gain = 105,000 . Detector capacitance = 150 pF A Pb attenuator was added between the source and the detector. How would this affect the pulse amplitude of the full-energy peak